1. Field of the Invention
The present invention relates to a speaker member having a vibrating plate part and an edge part. More specifically, the invention relates to a speaker member in which the vibrating plate part and edge part include the same material and both the vibrating plate part and the edge part satisfy the required characteristics.
2. Description of the Related Art
Generally, a vibrating plate and an edge of a speaker member are, made of different materials respectively. This is because the performances required for the vibrating plate and that required for the edge are quite different from each other. The vibrating plate pushes air around it to generate compressional wave, thereby generate acoustic wave. Therefore the vibrating plate is required to have enough strength to withstand the pressure of air. On the other hand, the edge is required to have enough flexibility to follow the movement of the vibrating plate as well as adequate vibration absorbing characteristics where the acoustic waves transmitted through the vibrating plate can be absorbed to the edge without reflection. In this way, performances required for the vibrating plate and the edge are different from each other. Therefore, in the process for preparing conventional speakers, the vibrating plate and the edge are made of different materials and the resultant two parts are adhered together in order to satisfy the respective requirements. Thus, in the process for manufacturing conventional speakers, material costs are required, respectively, for the vibrating plate and the edge; and preparing processes for each of the two parts and also, adhering process are required. The manufacture of conventional speakers are thus extremely high in cost and low in manufacturing efficiency.
In order to solve such problems, a method is proposed wherein the vibrating plate part and the edge are formed simultaneously, during the process of making a pulp cone. However, in this method, a special resin layer must be formed on the edge in order to prevent passage of air through the edge and to restrain the reflection of the vibrating plate. In this way, the manufacture of such a speaker has a large number of processes and is troublesome. The resultant edge, which vibrates in accordance with the vibration of the vibrating plate, is inadequate in durability and waterproof property since a pulp fiber, which is the core material of the edge, is low in strength. Moreover, the flexibility of the edge is inadequate because the resin layer is provided.
Another method is proposed, in which the vibrating plate and the edge are formed simultaneously by two-color injection molding. However in this method, resin materials that can be used are limited to thermoplastic resins. Therefore, the resultant speaker member is inadequate in heat resistance and elastic modulus.
Furthermore, a method has been proposed, in which a resin film or metal foil is formed into a shape of a cone- or dome-shaped vibrating plate, and the film or the foil is also formed into a roll-shaped edge. However, in this method, no measures are taken for satisfying the above-mentioned conflicting requirements for the vibrating plate and edge, and thus the strength of the edge is the same as the strength of the vibrating plate. An adequate amplitude of vibration, therefore, cannot be obtained. Furthermore, since the edge has hardly any vibration absorbing characteristics, a speaker for practical use cannot be obtained.
Among flat speakers, there are speakers containing a member that do not have an edge. However, flat speakers containing a member that has an edge is generally used. This member is obtained, as in the process for preparing a speaker having a cone shaped vibrating plate, by adhering a vibrating plate together with an edge, the vibrating plate and the edge being made of different material from each other. Furthermore, conventional flat vibrating plates use foamed polystyrene materials in order to obtain high strength, greater thickness, and lighter weight. In such a flat vibrating plate, the internal loss is small, therefore, break up vibration occurs readily. As a result, a peak-dip difference in vibration characteristics (vertical fluctuation of the sound pressure level in vibrationxe2x80x94sound pressure carve) becomes large. Although flat vibrating plates made of aluminum honeycomb are also used, such a flat vibrating plate is also small in internal loss and thus large in the peak-dip difference and, therefore, generates a distinctive, peculiar sound.
Though attempts have thus been made to form the vibrating plate and the edge simultaneously, a speaker member with which the respective requirements of the vibrating plate and the edge are satisfied have not been obtained.
A speaker member in which a vibrating plate part and an edge part are formed readily and in which both the vibrating plate part and the edge part are excellent in the required performance is thus strongly desired.
The present invention relates to a speaker member comprising:
(a) a vibrating plate part comprising a base material, a part of the base material being impregnated with a thermosetting resin; and
(b) an edge part containing the same base material as that of the vibrating plate.
In a preferred embodiment, said base material is a laminated body having at least two non-woven fabric layers and a resin film layer disposed between said non-woven fabric layers.
In a preferred embodiment, said non-woven fabric layer includes a non-woven fabric layer made of para-aramid fiber, meta-aramid fiber, rayon fiber, cotton fiber, ultra-high strength polyethylene fiber, or polyarylate fiber.
In a preferred embodiment, said resin film layer is comprised of a thermoplastic elastomer.
In a preferred embodiment, said thermoplastic elastomer is selected from the group consisting of urethane elastomers, amide elastomers, olefin elastomers, styrene elastomers, polyester elastomers, and ethylene/vinyl acetate elastomers.
In another preferred embodiment, said base material is a laminated body having at least two first non-woven fabric layers and a second non-woven fabric layer disposed between said non-woven fabric layers.
In a more preferred embodiment, said second non-woven fabric layer is made of thermoplastic elastomer fiber.
In a preferred embodiment, said thermoplastic elastomer fiber is selected from the group consisting of urethane elastomer fibers, amide elastomer fibers, olefin elastomer fibers, styrene elastomer fibers, polyester elastomer fibers, and ethylene/vinyl acetate elastomer fibers.
In a preferred embodiment, said base material is a laminated body having at least two non-woven fabric layers and an elastic woven fabric layer disposed between said non-woven fabric layers.
In a preferred embodiment, said elastic woven fabric layer is made of saturated polyester fiber.
In more preferred embodiment, said saturated polyester fiber is a poly(trimethyleneterephthalate) fiber.
In yet another preferred embodiment, said base material is a non-woven fabric made of thermoplastic elastomer fiber.
In a preferred embodiment, said base material is a woven fabric.
In a more preferred embodiment, said woven fabric base material is an elastic woven fabric made of saturated polyester fiber.
In a preferred embodiment, said saturated polyester fiber is a poly(trimethyleneterephthalate) fiber.
In a preferred embodiment, said thermosetting resin is a unsaturated polyester resin.
In a preferred embodiment, said thermosetting resin further contains short fibers of a natural fiber, a regenerated fiber or a synthetic fiber, or a mixture thereof.
In a preferred embodiment, said edge part contains a base material impregnated with a photocurable resin.
In more preferred embodiment, said photocurable resin is an acrylic resin.
In a preferred embodiment, said edge part contains a thermosetting resin that is different from the thermosetting resin in said vibrating plate part.
In yet another preferred embodiment, the thermosetting resin contained in the edge part further contains short fibers of a natural fiber, a regenerated fiber or a synthetic fiber, or a mixture thereof.
In more preferred embodiment, said thermosetting resin contained in the edge part is a thermosetting polyether urea elastomer.
In a preferred embodiment, said vibrating plate part has a cone shape.
In yet another preferred embodiment, said vibrating plate part has a flat shape.
In a preferred embodiment, said vibrating plate part has a reinforcing part.
The present invention also relates to a method of manufacturing a speaker member comprising the steps of:
forming a base material,
impregnating a portion of the base material with a thermosetting resin wherein the portion is to be a vibrating plate part, and
curing said impregnated thermosetting resin so as to form the vibrating plate part, and simultaneously forming an edge part.
In a preferred embodiment, said base material is a laminated body having two non-woven fabric layers and a resin film layer disposed between the non-woven fabric layers, and wherein said impregnated thermosetting resin is cured to form the vibrating plate part, and said resin film layer is simultaneously melted and solidified to form the edge part.
In a preferred embodiment, said base material is a laminated body having at least two first non-woven fabric layers and a second non-woven fabric layer disposed between said first non-woven fabric layers, and wherein the vibrating plate part is formed by curing said impregnated thermosetting resin and the edge part is simultaneously formed by melting and solidifying said second non-woven fabric layer.
In a preferred embodiment, said base material is a laminated body having at least two non-woven fabric layers and an elastic woven fabric layer disposed between said non-woven fabric layers, and wherein the vibrating plate part is formed by curing said impregnated thermosetting resin and the edge part is simultaneously formed by melting and solidifying said elastic woven fabric layer.
In yet another preferred embodiment, said base material is a non-woven fabric layer made of elastomer fiber, and wherein the vibrating plate part is formed by curing said impregnated thermosetting resin and the edge part is simultaneously formed by melting and solidifying said base material.
In a preferred embodiment, said base material is an elastic woven fabric layer made of saturated polyester fiber, and wherein the vibrating plate part is formed by curing said impregnated thermosetting resin and the edge part is simultaneously formed by melting and solidifying said base material.
The present invention further related to a method for manufacturing a speaker member comprising the steps of:
forming a base material,
impregnating a portion of said base material with a thermosetting resin, wherein the portion is to be a vibrating plate part,
impregnating a portion of said base material with a photocurable resin, wherein the portion is to be the edge part,
forming the vibrating plate part by curing said impregnated thermosetting resin, and
forming the edge part by curing said impregnated photocurable resin.
The present invention also relates to a method for manufacturing a speaker member comprising the steps of:
forming a base material,
impregnating a portion of said base material with a first thermosetting resin, wherein the portion is to be the vibrating plate part,
impregnating a portion of said base material with a second thermosetting resin, wherein the portion is to be the edge part, and
curing said impregnated first and second thermosetting serins, resulting in a simultaneous formation of the vibrating plate part at the edge part.